Tear-strip or rip-strip sheet metal containers are well known, and such containers have long been in use to store or package foods for subsequent use; however, it has been invariably the case that, when foods such as soups or vegetables are store therein, the foods require heating from the outside or a source exterior to the container, upon opening the container by removal of the tear-strip.
These containers have usually been provided with soldered lock and lap side seams, wherein the portion of the seam at the tearing strip is a lap portion. Alternatively, an organic adhesive or cement has been used instead of solder in order to bond together various layers of the side seams.
When using a cemented side seam, it has been advantageous to continue the lock portion of the seam through the tearing-strip area and to interfold or double-up the tearing-strip tongue into the seam as one of the seam hooks, in order to provide for the usual overlap projection of the tongue on the outside of the can to allow engagement of the tongue with a conventional key, in order to remove the tearing-strip to open the can.
However, whether these containers have been provided with soldered lock and lap side seams, or an organic adhesive or a cement to bond together the various layers of the side seams, neither of these techniques are known to allow the contents of the container to be heated from a heating source or heat producing materials that are integral with and form part of the container or can.